1. Field of the Invention
The present invention relates to a liquid-crystalline polymer composition and a method for producing the composition, and to a molded article and a planate connector using the composition.
2. Description of the Related Art
Thermoplastic resin, which is excellent in moldability, is often used for electronic parts such as a printed circuit board, a semiconductor, a connector, a relay and a switch. On the other hand, in addition to moldability, excellent heat resistance and strength are also needed particularly in electronic parts used for surface mounting, and liquid-crystalline polymer is used as the material which meets such demands. In order to apply the liquid-crystalline polymer to various applications, attempts to improve various characteristics of the polymers have been actively performed.
For example, aiming at improving the moldability of the liquid-crystalline polymer, methods for improving flowability of the liquid-crystalline polymer by adding various materials are proposed. Specifically, the following methods have been disclosed: a method for adding an oligomer of p-hydroxybenzoic acid to a liquid-crystalline polymer (Japanese Patent Application Laid-open Publication No. 3-252457 corresponding to U.S. Pat. No. 5,244,975); a method for blending a liquid-crystalline polymer of low molecular weight with a liquid-crystalline polymer (Japanese Patent Application Laid-open Publication No. 3-252457 corresponding to U.S. Pat. No. 5,244,975 and Japanese Patent No. 2823873 corresponding to U.S. Pat. No. 5,766,507); and a method for mixing liquid-crystalline polyesters resins having different melting points (Japanese Patent Application Laid-open Publication No. 2002-249647 corresponding to U.S. Pat. No. 6,656,386).
Moreover, in recent years, a miniaturization of electronic parts and making them to be thin-walled are advanced, and as for liquid-crystalline polymers used for electronic parts, especially for connectors, it is required to decrease the generation of warpage in a molded article while maintaining excellent flowability, heat resistance and mechanical strength.
Trying to obtain such a liquid-crystalline polymers decreasing the generation of warpage, the one in which glass fiber is filled to a liquid-crystalline polyester resin so that a number average fiber length may become 0.12 to 0.25 mm (Japanese Patent No. 3045065), the one in which fibrous fillers and granular fillers are added to a liquid-crystalline polymer (Japanese Patent Application Laid-open Publication No. 2000-178443 corresponding to U.S. Pat. No. 6,702,955), the one in which fibrous and/or plate-like inorganic fillers are used in the combination of two kinds of liquid-crystalline polymers with different flow temperatures (Japanese Patent Application Laid-open Publication No. 10-219085 corresponding to U.S. Pat. No. 5,976,406) and the like have been proposed. In addition, aiming at obtaining a liquid-crystalline polymer which may have good heat resistance and flowability and may decrease the generation of warpage in the molded article even when a thinner molded article is formed, the one in which fibrous inorganic fillers and/or plate-like inorganic fillers which meet the prescribed conditions are added to a prescribed liquid-crystalline polyester (Japanese Patent Application Laid-open Publication No. 2002-294038 corresponding to U.S. Pat. No. 6,733,691) has been proposed.
Moreover, the liquid-crystalline polymer composition in which rigidity may be improved without accompanying lowering flowability, compared to a case when each component of liquid-crystalline polymers is singly used (Japanese Patent Application Laid-Open No. 2005-298772), also has been proposed.